Disc cartridge

ABSTRACT

A disc cartridge housing a disc-shaped recording medium in a main cartridge body portion is disclosed. The disc cartridge includes a main cartridge body portion having a circular medium housing section for rotationally housing a disc-shaped recording medium, a recording and/or reproducing opening for exposing at least a portion of the disc-shaped recording medium to outside and a driving opening for allowing intrusion of a rotating driving unit adapted for rotationally driving the disc-shaped recording medium. The disc cartridge also includes a shutter mechanism having a shutter member rotated along the major surface of the main cartridge body unit in a region provided with the medium housing section to open/close the recording and/or reproducing opening and a plurality of cartridge supporting portions at plural corner regions of larger area outside a region provided with the medium housing section of the main cartridge body unit. The disc cartridge is loaded on the recording and/or reproducing apparatus by the cartridge supporting portions being supported by a positioning mechanism provided on the recording and/or reproducing apparatus.

This is a continuation of application Ser. No. 10/262,007, filed Oct. 1,2002 now U.S. Pat. No. 6,810,005, which is a continuation of Ser. No.09/350,392, filed Jul. 9, 1999, now U.S. Pat. No. 6,473,392.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a disc cartridge for housing a disc-shapedrecording medium, such as an optical disc or a magneto-optical disc,loaded on a recording and/or reproducing apparatus.

2. Description of the Related Art

There has hitherto been used a disc cartridge housing an optical disc, amagneto-optical disc or a magnetic disc and which is loaded therewith ona recording and/or reproducing apparatus.

As this type of the disc cartridge, there is known such a devicedescribed in the U.S. Pat. No. 4,510,546.

With the disc cartridge described in these publications, a disc as ainformation recording medium is rotationally housed within a maincartridge body unit which is rectangular in shape. The main cartridgebody unit has a recording and/or reproducing opening for allowing aportion of the housed disc to be exposed to outside across the inner andouter rims of the disc. This main cartridge body unit carries a shuttermember, rectangular in cross-section, adapted to be moved along thefront side of the main cartridge body unit for opening/closing therecording and/or reproducing opening. This shutter member is movedparallel to the one side at a center portion of the main cartridge bodyunit along the front surface of the main cartridge body unit toopen/close the recording and/or reproducing opening, so that, at thecorner portions of the rectangular main cartridge body unit, there areformed regions not covered by the shutter member and not faced by themagnetic disc. Thus, in these regions, there are provided cartridgesupporting portions engaged or supported by the positioning pinsprovided on the recording and/or reproducing apparatus when the disccartridge is loaded on the recording and/or reproducing apparatus.

As a disc cartridge housing a disc as an information recording medium,there is known such a one as described in the U.S. Pat. No. 4,614,990.

In the disc cartridge described in this Publication, a disc is rotatablyhoused in a rectangular main cartridge body unit. The main cartridgebody unit is provided with a recording and/or reproducing opening forexposing part of the magnetic disc housed therein to outside across theinner and outer rims of the disc. The disc cartridge is provided with arecording and/or reproducing opening larger in size than the maincartridge body unit.

As a disc cartridge housing a disc as an information recording medium,there is known such one as disclosed in the U.S. Pat. No. 5,570,252. Thedisc cartridge disclosed in this Publication has an opening in a lateralsurface of the main cartridge body unit. The magnetic head is introducedvia this opening into the inside of the disc cartridge into slidingcontact with the signal recording region of the magnetic disc. In thisdisc cartridge, the shutter member adapted for opening/closing theopening is mounted for performing movement along a lateral side of themain cartridge body unit.

Meanwhile, with the disc cartridge disclosed in the U.S. Pat. No.4,510,546, in which the shutter member is moved in parallel along thefront surface of the main cartridge body unit to open/close therecording and/or reproducing opening, it is difficult to provide acartridge supporting portion sized sufficient to support the disccartridge in stability on both sides of the front surface of the movingmain cartridge body unit, such that it is difficult to load the disccartridge on the recording and/or reproducing apparatus in stability.

Also, the disc cartridge as disclosed in the U.S. Pat. No. 4,614,990 isprovided with a recording and/or reproducing opening larger in size thanthe main cartridge body unit, the shutter member for opening/closing therecording and/or reproducing opening is also increased in size, andmoreover is mounted on the front side of the main cartridge body unit sothat the shutter member will be moved from the center portion of themain cartridge body unit to the vicinity of the lateral sides of themain cartridge body unit. Therefore, a cartridge supporting portionengaged or supported by the positioning pins provided on the recordingand/or reproducing apparatus cannot be provided on a corner of the frontsurface along which is moved the shutter member of the main cartridgebody unit to render it difficult to load the disc cartridge on therecording and/or reproducing apparatus in stability.

Moreover, the disc cartridge disclosed in the U.S. Pat. No. 5,570,252,the magnetic head is inserted into the inside of the main cartridge bodyunit via a narrow opening formed in the lateral surface of the maincartridge body unit, there are imposed limitations on the recordingand/or reproducing mechanism that can be used. This disc cartridge isextremely difficult to apply for accommodating an optical disc used inconjunction with an optical pickup device. Also, the shutter member isadapted for opening/closing an opening narrow in width and longer thanit is wide, and hence it is narrow and elongated in profile to render itdifficult to realize a stable movement.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a disccartridge in which a cartridge supporting portion is provided in aregion of a larger area to render it possible to load the disc cartridgein stability in the recording and/or reproducing apparatus.

It is another object of the present invention to provide a disccartridge in which an opening for exposing the disc-shaped recordingmedium to outside can be positively opened/closed despite the largersize of the opening and the disc cartridge can be loaded in stability onthe recording and/or reproducing apparatus.

It is still another object of the present invention- to provide a disccartridge which can be inserted easily into the recording and/orreproducing apparatus.

It is yet another object of the present invention to provide a disccartridge in which a shutter member for opening/closing the openingprovided in the main cartridge body unit can be moved in stability toassure positive protection of the shutter member.

In view of the above objects, the present invention provides a disccartridge for housing a disc-shaped recording medium adapted forrecording information signals thereon, including a disc-shaped recordingmedium, a main cartridge body unit including a circular medium housingsection for rotationally housing the disc-shaped recording medium, arecording and/or reproducing opening for exposing at least a portion ofthe disc-shaped recording medium to outside, and a driving opening forallowing intrusion of rotating driving means for rotationally drivingthe disc-shaped recording medium, a shutter mechanism is rotated alongthe major surface of the main cartridge body unit within a regionprovided with the medium housing section of the main cartridge body unitto open/close at least the recording and/or reproducing opening, and aplurality of cartridge supporting portions provided at a plurality ofcorners outside the region provided with the medium housing section ofthe main cartridge body unit. The cartridge supporting portions issupported by positioning means provided on the recording and/orreproducing apparatus.

At the plural corners of the main cartridge body unit outside the regionf the main cartridge body unit provided with the medium housing section,there may be provided plural regions of a larger area. If cartridgesupporting portions are provided in these regions, the disc cartridgemay be loaded in stability on the recording and/or reproducingapparatus.

The front surface of the main cartridge body unit of the disc cartridgeaccording to the present invention, by which the main cartridge bodyunit is inserted into the recording and/or reproducing apparatus, isformed to a continuously arcuate shape having a radius larger than thatof the arc of the medium housing section, whereby a region of a largerarea in which to provide cartridge supporting portions is provided onboth sides of the front surface. Moreover, the disc cartridge can beinserted easily into the recording and/or reproducing apparatus byhaving the arcuate front surface as an inserting end surface.

Also, if a lock mechanism for regulating the opening of the shuttermechanism is provided in the region surrounded by the medium housingsection in the main cartridge body unit and the front surface of themain cartridge body unit, the shutter mechanism can be positively heldin its closure position. Since the region surrounded by the mediumhousing section and the front surface of the main cartridge body unit isable to constitute a spacing of a larger area, the lock mechanism can bereadily constructed which is able to hold the shutter mechanismreliably.

In the disc cartridge according to the present invention, the region inwhich the shutter member is rotated is a spacing defined by facing innerand outer wall sections to allow for entrance of the shutter member.When rotated to the position of opening the recording and/or reproducingopening provided in the main cartridge body unit, at least a portion ofthe shutter member is housed within a spacing defined between the innerand outer wall sections.

The present invention also provides a disc cartridge for housing adisc-shaped recording medium adapted for recording information signalsthereon, including a disc-shaped recording medium, a main cartridge bodyunit including a circular medium housing section for rotationallyhousing the disc-shaped recording medium, a recording and/or reproducingopening for exposing at least a portion of the disc-shaped recordingmedium to outside, and a driving opening for allowing intrusion ofrotating driving means for rotationally driving the disc-shapedrecording medium, a shutter mechanism including a first shutter memberrotated along the major surface of the main cartridge body unit within aregion provided with the medium housing section to open/close at leastthe recording and/or reproducing opening and a second shutter member foropening/closing the driving opening, a shutter housing sectionconstituted by an inner wall member and an outer wall member facing eachother, and a plurality of cartridge supporting portions provided outsidethe region of the shutter housing section so as to be supported bypositioning means provided on the recording and/or reproducingapparatus. The shutter housing section is provided outside of a regionof movement of the shutter mechanism and houses at least a portion ofthe shutter mechanism.

Other objects and advantages of the present invention will becomeapparent from the following detailed description of the preferredembodiments and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a disc cartridge according to thepresent invention.

FIG. 2 is a perspective view of a disc cartridge according to thepresent invention looking from the bottom side provided with a shuttermechanism and showing both a recording and/or reproducing opening and adriving opening closed by the shutter mechanism.

FIG. 3 is an exploded perspective view of the disc cartridge.

FIG. 4 is a plan view of the disc cartridge showing the state of closureof the recording and/or reproducing opening and the driving opening.

FIG. 5 is a transverse cross-sectional view of the disc cartridge.

FIG. 6 is a plan view of the disc cartridge showing the opened state ofthe recording and/or reproducing opening and the driving opening.

FIG. 7, similarly to FIG. 6, is a bottom view of a disc cartridgeshowing the closed state of the recording and/or reproducing opening andthe driving opening.

FIG. 8 is a perspective view of the disc cartridge showing the recordingand/or reproducing opening and the driving opening in the opened state.

FIG. 9 is an exploded perspective view showing a modification of thedisc cartridge according to the present invention.

FIG. 10 is a plan view of the disc cartridge showing the state in whichthe recording and/or reproducing opening and the driving opening areclosed.

FIG. 11 is a longitudinal cross-sectional of the disc cartridge.

FIG. 12 is a longitudinal cross-sectional view of the disc cartridge inwhich the recording and/or reproducing opening and the driving openingare opened.

FIG. 13 is a bottom view of the disc cartridge showing the state inwhich the recording and/or reproducing opening and the driving openingare closed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, a disc cartridge of the present inventionwill be explained in detail.

A disc cartridge 1 of the present invention houses an optical disc 2 ofa recordable type for re-recording the information, such as the audio orvideo information, using a disc-shaped recording medium, or houses areplay-only optical disc 2 having the pre-recorded audio or videoinformation. The disc cartridge 1 rotationally houses an optical disc 2in a main cartridge body unit 5 constituted by an upper half cartridge 3and a lower half cartridge 4, as shown in FIGS. 1 and 2.

The optical disc 2, housed in the main cartridge body unit 5, has acenter opening 6, and a hub 7, formed by a plate of a magnetic material,such as metal, for closing the center opening 6. The optical disc 2 isset on a disc table of a rotational driving mechanism of the recordingand/or reproducing apparatus, and has the hub 7 attracted by a magnetprovided on the disc table, so that the optical disc 2 will be rotatedin unison with the disc table. When the optical disc 2 is loaded on thedisc table, a centering portion provided at the center of the disc tableis engaged with the center opening 6 to achieve centering so that thecenter of rotation of the optical disc 2 will be coincident with thecenter of rotation of the disc table.

The main cartridge body unit 5, rotationally housing the optical disc 2,is combined from an upper half cartridge 3 and a lower half cartridge 4abutted and connected to each other, as shown in FIG. 3. The upper halfcartridge 3 and the lower half cartridge 4 are substantially rectangularin shape and molded from synthetic resin, as shown in FIG. 3.

The upper half cartridge 3; constituting the main cartridge body unit 5,has an upstanding peripheral wall 8 constituting an peripheral wall ofthe main cartridge body unit 5. The upper half cartridge 3 has a frontsurface 3 a, as an inserting end of the upper half cartridge 3 into therecording and/or reproducing apparatus, presents a continuous arcuatesurface. The arcuate front surface 3 a has a mid cut-out 3 b into whichis intruded a recording/reproducing mechanism provided on the recordingand/or reproducing apparatus. The front surface of the upper halfcartridge 3 also operates as a front surface of the main cartridge bodyunit 5. The opposite lateral surfaces of the main cartridge body unit 3perpendicular to the front surface 3 a of the upper half cartridge 3operating as the inserting end into the recording and/or reproducingapparatus are formed as flat surfaces to permit the inserting end intothe recording and/or reproducing apparatus to be recognized as such. Thedisc cartridge can also be distinguished from the rectangular disccartridge widely recognized as the disc cartridge.

Referring to FIGS. 1 and 2, only the front surface 3 a of the upper halfcartridge 3 constituting the front surface of the main cartridge bodyunit 5 is formed as an arcuate surface, while the lateral surfacesthereof perpendicular to the front surface 3 a are linear flat surfacesparallel to each other, so that these lateral surfacers act as insertingguide surfaces at the time of insertion and detachment with respect tothe recording and/or reproducing apparatus to realize stable lateralsurfaces of the recording and/or reproducing apparatus.

The back surface of the main cartridge body unit 5 opposite to thearcuate front surface 3 a may also be arcuately shaped. In this case,the arc of the back surface is preferably larger than the arc of thefront surface 3 a to permit distinction from the front side of the disccartridge 1.

With the disc cartridge 1, since only the front surface 3 a of whichoperating as an inserting end into the recording and/or reproducingapparatus, is designed as an arcuate surface, the disc cartridge 1 canbe reduced in plan size as compared to the optical disc 2 housed thereinto permit reduction in size of the recording and/or reproducingapparatus employing the disc cartridge 1.

Referring to FIGS. 2 and 3, the corners on the back side opposite to thearcuately-shaped front surface 3 a of the upper half cartridge 3 areformed with tubular positioning portions 9 engaged by positioning pinson the recording and/or reproducing apparatus. Each of the positioningportions 9 has its distal end opened and has its proximal end closed bythe upper half cartridge 3.

The lower half cartridge 4, abutted against the upper half cartridge 3to constitute the main cartridge body unit 5, is arcuate with acurvature larger than that of the front surface 3 a of the upper halfcartridge 3. That is, an arcuate front surface 4 a of the lower halfcartridge 4 is arcuate with a radius smaller than that of the frontsurface 3 a of the upper half cartridge 3, as shown in FIG. 3. Theportions of the lower half cartridge 4 other than the front surface 4 aare shaped similarly to the upper half cartridge 3. That is, theopposite lateral sides perpendicular to the front surface 4 a of thelower half cartridge 4 are parallel to each other, with the back surfaceopposite to the front surface 4 a of the lower half cartridge 4 beingformed as planar surfaces.

On the inner major surface of the lower half cartridge 4 is formedupright an arcuate housing section forming wall 10 constituting acircular disc housing section 11. This housing section forming wall 10has the same radius of curvature as that of the front surface 4 a. Onthe outer perimeter of the lower half cartridge 4 is formed anupstanding peripheral wall 12 abutted against the upstanding peripheralwall 8 constituting the peripheral wall of the main cartridge body unit5 formed upright on the outer rim of the upper half cartridge 3. Insubstantially triangular regions of the back surface side of the lowerhalf cartridge 4 surrounded by the upstanding peripheral wall 12 and thehousing section forming wall 10, there are formed holes 14 into whichare fitted the positioning portions 9 provided on the upper halfcartridge 3.

Referring to FIGS. 2 and 3, the lower half cartridge 4 is formed with arecording and/or reproducing opening 15 and a driving opening 16. Therecording and/or reproducing opening 15 is adapted for exposing aportion of the signal recording region of the optical disc 2 housed inthe disc housing section 11 to outside across the inner and outer rimsof the disc, and for facing recording and/or reproducing means, such asan optical pickup device, while the driving opening 16 is adapted topermit entrance of the turntable of the rotational driving mechanismprovided on the recording and/or reproducing apparatus. In the presentdisc cartridge 1, the recording and/or reproducing opening 15 is formedin continuation with the driving opening 16.

Although the recording and/or reproducing opening 15 may be providedindependently of the driving opening 16, there is then provided apartitioning connection portion between the openings 15, 16. If theconnecting portion is provided in this manner, it becomes impossible toshift the recording and/or reproducing mechanism, such as the opticalpickup device, adapted to scan the signal recording region of theoptical disc 2, such that sufficient recording capacity of the opticaldisc 2 cannot be achieved. Therefore, the recording and/or reproducingopening 15 preferably is formed as one with the driving opening 16.

Referring to FIG. 3, the recording and/or reproducing opening 15 isformed substantially as a rectangular opening extending from thevicinity of the mid portion of the disc housing section 11 up to thefront surface 4 a of the lower half cartridge 4. This opening 15,continuing to the driving opening 16, is formed by opening the frontsurface 4 a of the lower half cartridge 4. The driving opening 16 issubstantially circular and is positioned at a mid portion of the dischousing section 11. On the periphery of the inner rim of the drivingopening 16 is formed a disc supporting portion 16 a supporting the rimof the center opening 6 of the optical disc 2 housed in the disc housingsection 11.

In the main cartridge body unit 5, since the front surface 4 a of thelower half cartridge 4 has a curvature larger than the curvature of thefront surface 3 a of the upper half cartridge 3, the corners of thefront surface of the upper half cartridge 3 are protruded from thecorners on the upper half cartridge 3 when the upper and lower halfcartridges 3, 4 are abutted against each other, as shown in FIG. 4. Theupstanding peripheral wall 8, formed on the portion of the upper halfcartridge 3 protruded from the lower half cartridge 4, is formed to aheight corresponding to the thickness of the main cartridge body unit 5.

In a lateral surface perpendicular to the front surface of the maincartridge body unit 5 is formed an engagement groove 17 for a shutteropening/closing member, as shown in FIG. 2. When the upper and lowerhalf cartridges 3, 4 are abutted against each other, the engagementgroove 17 for a shutter opening/closing member is abutted against agroove 17 a formed in the upstanding peripheral wall 8 of the upper halfcartridge 3 and against a recess 17 b formed in the upstandingperipheral wall 12. When the disc cartridge 1 is inserted into therecording and/or reproducing apparatus, a shutter opening/closing memberconstituting the shutter opening/closing mechanism provided on therecording and/or reproducing apparatus is engaged in the engagementgroove 17 for a shutter opening/closing member for movement therein. Theengagement groove 17 for a shutter opening/closing member is formed witha through-hole 18 into which is protruded part of a lock member 30 aslater explained.

The front surface 3 a of the upper half cartridge 3 constituting themain cartridge body unit 5 is formed with an inner wall 19 having thesame curvature as that of the front surface 4 a of the lower halfcartridge 4. When the upper and lower half cartridges 3, 4 are abuttedagainst each other, as shown in FIGS. 4 and 5, the inner wall section 19is abutted against the inner surface of the lower half cartridge 4 alongthe outer periphery of the arcuate housing section forming wall 10provided on the lower half cartridge 4. In the inner wall section 19 ofthe upper half cartridge 3 and in the peripheral wall 10 of the lowerhalf cartridge 4 is formed a shutter guide groove 20 for guiding theopening/closure movement of a first shutter member 25 of the shuttermechanism 23, as shown in FIGS. 4 and 5.

At both corners towards the front surface of the main cartridge bodyunit 5 are formed a pair of substantially triangular regions surroundedby the upstanding peripheral wall 8 and the inner wall section 19 of theupper half cartridge 3, as shown in FIG. 4. In a region of the maincartridge body unit 5 provided with the engagement groove 17 for ashutter opening/closing member provided in the main cartridge body unit5, there is protruded a supporting shaft 21 for rotationally supportinga lock member 30, as shown in FIG. 4. In the opposite side similarregion, there is provided a cover member supporting protrusion 22 forsupporting a cover member 38.

In the bottom surface of the lower half cartridge 4 constituting themain cartridge body unit 5, there is provided a recessed shuttermounting portion 24 in which to mount the shutter mechanism 23 adaptedfor opening/closing the recording and/or reproducing opening 15 and thedriving opening 16, as shown in FIGS. 4 and 5. The shutter mountingportion 24 is formed over an extent through which is slid the shuttermechanism 23 for opening/closing the recording and/or reproducingopening 15 and the driving opening 16.

The shutter mechanism 23 arranged on the shutter mounting portion 24 ismade up of a first shutter member 25 for opening/closing the recordingand/or reproducing opening 15 and a second shutter member 26 foropening/closing the driving opening 16. The first shutter member 25 andthe second shutter member 26 are arranged in a co-planar relation in theshutter mounting portion 24. The shutter mechanism 23 may also be sodesigned that the first shutter member 25 mainly opens/closes therecording and/or reproducing opening 15, while the second shutter member26 mainly opens/closes the driving opening 16. That is, the firstshutter member 25 may, for example, be designed so that the secondshutter member 26 is moved to affect a portion of the opening to beopened/closed by the other shutter member to open/close the recordingand/or reproducing opening 15 and the driving opening 16.

The first shutter member 25 is formed of synthetic resin or metal and ismade up of a shutter portion 25 a, formed as a flat plate, a movementguide portion 25 b formed upright on a side of the shutter portion 25 a,and an actuating portion 25 c protruded from one end of the movementguide portion 25 b, as shown in FIG. 3. The first shutter member 25 ismounted on the main cartridge body unit 5, with the shutter portion 25 abeing positioned in the shutter mounting portion 24 formed in the lowerhalf cartridge 4 and with the movement guide portion 25 b and theactuating portion 25 c being positioned in the shutter guide groove 20.The shutter portion 25 a is formed as substantially trapezoidal shape ofa size sufficient to close the recording and/or reproducing opening 15,and carries on its lateral side an arcuate portion of the same curvatureas that of the front surface 4 a of the lower half cartridge 4. Thisshutter portion 25 a is rotated in the direction indicated by arrows A1and A2 in FIG. 4, with the center of the disc housing section 11 asvirtual center, for opening/closing the recording and/or reproducingopening 15.

The shutter portion 25 a has a side edge opposite to its arcuate portionabutted against the second shutter member 26. The shutter portion 25 ahas an overlapping portion 25 e on a side edge abutted against thesecond shutter member 26. This overlapping portion 25 e is overlappedwith a side of the second shutter member 26. This overlapping portion 25e may also be provided on the second shutter member 26. The shutterportion 25 a is provided with a shaft-shaped guide protrusion 27 on itsmajor surface, that is on a surface opposite to the shutter mountingportion 24. The shaft-shaped guide protrusion 27 regulates the movementposition of the shutter portion 25 a. This shaft-shaped guide protrusion27 is provided on the side of the shutter portion 25 a abutted againstthe second shutter member 26. The shaft-shaped guide protrusion 27 holdsa certain thickness in a portion of the shutter portion 25 a to preventthe first shutter member 25 and the second shutter member 26 from beingshifted into an overlapping relation with each other at the time of theopening/closure operation.

The movement guide portion 25 b is formed subsequently upright withrespect to the shutter portion 25 a for extending along an arcuateportion formed on one side of the shutter portion 25 a. This movementguide portion 25 b is formed in an arcuate shape of the same curvatureas that of the shutter guide groove 20 and is arranged for movementtherein in the direction indicated by arrows A1 and A2 in FIG. 4. Themovement guide portion 25 b is of a length longer than that of thearcuate portion of the shutter portion 25 a so as to reach the vicinityof an end of a shutter guide groove 20 to control the movement so thatthe first shutter member 25 will not be moved in excess of a pre-setdistance in the direction indicated by arrow A2 in FIG. 4. The movementguide portion 25 b is provided with a recess 25 d into which is intrudedthe recording/reproducing mechanism, such as an optical pickup, when theshutter mechanism 23 is opened.

In the closure position of the shutter mechanism 23, the movement guideportion 25 b closes the cut-out 3 b formed in the front side of the maincartridge body unit 5, as shown in FIG. 1. When the shutter mechanism 23is opened, as shown in FIG. 8, the recess 25 d is moved to the cut-out 3b to create an opening in the front side which will permit the opticaldisc 2 to be exposed to outside, as shown in FIG. 8. That is, the disccartridge 1 is constructed so that the height H2 in the opened state ofthe shutter mechanism 23 as shown in FIG. 8 will be lower than theheight H1 in the closed state of the shutter mechanism 23, as shown inFIG. 2. By providing the recess 25 d in the disc cartridge 1, therecording/reproducing mechanism provided on the recording and/orreproducing apparatus can be moved towards and away from the opticaldisc 2. By reducing the distance between the optical disc 2 and therecording/reproducing mechanism, it is possible to reduce the thicknessof the recording and/or reproducing apparatus employing the disccartridge 1.

The actuating portion 25 c provided on the first shutter member 25 isformed as an elastic or resilient member, and is of a thickness thinnerthan the movement guide portion 25 b. Similarly to the movement guideportion 25 b, the actuating portion 25 c is arranged within the shutterguide groove 20, with the distal end of the movement guide portion 25 bprotruding into the engagement groove 17 for the shutter opening/closingmember, as shown in FIG. 4. At the distal end of the actuating portion25 c, exposed to the engagement groove 17 for the shutteropening/closing member, there is formed an actuating lug 28. Theactuating portion 25 c is pulled into the inside of the engagementgroove 17 for the shutter opening/closing member, by the actuating lug28 engaging with a shutter opening/closure member of the shutteractuating mechanism of the recording and/or reproducing apparatus movedwithin the engagement groove 17 so as to be thrust by the shutteropening/closure member in the direction indicated by arrow C1 in FIG. 4.Partway in the actuating portion 25 c is bored a shutter retentionopening 29. This shutter retention opening 29 is engaged by a lock pawl30 a of a lock member 30 which is arranged in a substantially triangularrecess provided in a region between the upstanding peripheral wall 8 andthe inner wall section 19 of the upper half cartridge 3 and which isrotationally supported by a supporting shaft 21. The opening/closuremovement of the first shutter member 25 is controlled by the lock pawl30 a of the lock member 30 engaging in the shutter retention opening 29of the actuating portion 25 c.

Since the actuating portion 25 c is formed by an elastic or resilientmember, it is able to be moved smoothly, as it is deformed, in a pathalong the shutter guide groove 20 shaped by the combination of astraight line and a curve, as shown in FIG. 4.

The lock member 30 includes a lock pawl 30 a, an unlock lever 30 b,partially protruded from a through-hole 18 formed in the engagementgroove 17 for the shutter opening/closing member and an elastic member30 c, such as a spring plate, which biases the lock member 30 in thedirection indicated by arrow D in FIG. 4, that is in a direction ofengaging the distal end of the lock pawl 30 a in the shutter retentionopening 29.

Similarly to the first shutter member 25, the second shutter member 26is substantially formed to a sector-shape, from a synthetic resin ormetal, to a size sufficient to close the driving opening 16, as shown inFIGS. 3 and 4. The second shutter member 26 is formed with areinforcement 31 along which the guide protrusion 27 of the firstshutter member 25 is abutted and moved. This reinforcement 31 increasesthe contact area with the first shutter member 25 to assure theopening/closing operation of the second shutter member 26. The secondshutter member 26 is provided with an engagement pin 33 near an endthereof for engagement in an engagement opening 32 bored in the lowerhalf cartridge 4. The second shutter member 26 is moved in the directionindicated by arrows B1 and B2 in FIG. 4, about the engagement pin 33 asthe center, for opening/closing the driving opening 16.

The second shutter member 26 is rotationally biased in the directionindicated by arrow B2 in FIG. 4 by a torsion coil spring 34 arranged inthe recess formed in the lower half cartridge 4, as shown in FIG. 4. Thetorsion coil spring 34 is made up of an annular coil portion 34 a,engaged by the engagement pin 33 inserted into the engagement opening 32so as to be protruded into the substantially triangular recess in thelower half cartridge 4, an elastic first arm 34 b extended from the coilportion 34 a, and a second arm 34 c longer in length than the arm 34 b.The distal end of the second arm 34 c of the torsion coil spring 34 issecured to the lower half cartridge 4, while the first arm 34 bcompresses against a coil spring thrusting pin 36 inserted through asector-shaped elongated opening 35 formed in the lower half cartridge 4so as to be protruded into the substantially triangular recess in thelower half cartridge 4. The elongated opening 35 is formed in the lowerhalf cartridge 4 in adjacency to the engagement pin 33 of the secondshutter member 26.

In the event of the opening/closure operation by the first shuttermember 25 and the second shutter member 26 of the shutter mechanism 23,as shown in FIGS. 4 and 6, the guide protrusion 27 formed on the surfaceof the shutter mechanism 23 and the reinforcement 31 are shifted. Forthis reason, the main cartridge body unit 5 is formed with a shutterguide opening 37 for extending over a range of shifting of the guideprotrusion 27 and the reinforcement 31 of the lower half cartridge 4.

When the upper half cartridge 3 and the lower half cartridge 4 areabutted against and bonded to each other by thermal fusion or with anadhesive to form the main cartridge body unit 5, and the shuttermechanism 23 is arranged on the shutter mounting portion 24 provided onthe main cartridge body unit 5, there is mounted a cover member 38 onthe bottom side of the main cartridge body unit 5, that is on the sideof the lower half cartridge 4 carrying the shutter mounting portion 24.The portion of the cover member 38 in register with the recording and/orreproducing opening 15 and the driving opening 16 is cut out, whilethere is formed an opening 39 at a position in register with thepositioning portion 9 provided on the upper half cartridge 3 forexposing the opening end of the positioning portion 9 to outside. Thecover member 38 holds the shutter mechanism 23 arranged on the shuttermounting portion 24 to prevent the intrusion of dust and dirt into theinside of the main cartridge body unit 5. The cover member 38 issecured, such as with an adhesive, to the main cartridge body unit 5.The disc cartridge 1 is formed in the lower half cartridge 4 with therecording and/or reproducing opening 15 and the driving opening 16, asfirst openings, and with a cut-out in the cover member 38, as a secondopening, to provide the openings operative to expose the center opening6 of the recording region of the optical disc 2 to outside.

Meanwhile, since the shutter member provided on the routine disccartridge is mounted exteriorly of the main cartridge body unit, and ismoved along the outer surface of the main cartridge body unit, the dustand dirt affixed to the outer surface of the main cartridge body unit isaffixed to the back side of the shutter member to descend into theinside of the disc housing section.

In the disc cartridge 1 of the present invention, the first shuttermember 25 and the second shutter member 26 are provided in the housingspace defined between an inner wall constituted by the outer surface ofthe lower half cartridge 4 of the main cartridge body unit 5 and thecover member 38 arranged in an overlapping relation on the inner wall toconstitute an outer wall, so that there is no risk that the dust anddirt affixed to the outer side of the main cartridge body unit 5 beintruded into the inside of the cartridge housing section 11 to assurereliable protection of the optical disc 2 housed in the main cartridgebody unit 5.

The portion of the main cartridge body unit 5 where the first shuttermember 25 and the second shutter member 26 are arranged constitutes thelower major surface of the main cartridge body unit 5, it is notpossible to enlarge the space in which to hold the lower half cartridge4 and the cover member 38, or else the main cartridge body unit 5 isincreased in thickness. In the disc cartridge 1 according to the presentinvention, since the movement guide portion 25 b is moved along theshutter guide groove 20 constituted between the inner wall section 19 ofthe upper half cartridge 3 and the peripheral wall 10 of the lower halfcartridge 4 to cause rotation of the shutter portion 25 a, there is nonecessity for providing a supporting shaft at the center of rotation ofthe shutter portion 25 a, so that the bottom of the main cartridge bodyunit 5 can be reduced in thickness even if the spacing in which toaccommodate the shutter members 25, 26 is provided in the bottom of themain cartridge body unit 5, so that there is no fear of increasing thethickness of the main cartridge body unit 5.

In the disc cartridge 1 according to the present invention, there areprovided cartridge supporting portions 40 outwardly of the shuttermounting portion 24, that is at the four corners of the main cartridgebody unit 5 outside the range of movement of the shutter mechanism 23,as shown in FIG. 7. The cartridge supporting portions 40 are supportedby positioning pins provided on the recording and/or reproducingapparatus for setting the positions in the height-wise direction and inthe horizontal direction and height setting pins similarly provided onthe recording and/or reproducing apparatus for setting the positions inthe height-wise direction. The cartridge supporting portions 40 providedat the back side corners of the main cartridge body unit 5 are providedwith positioning portions 9 engaged by the positioning pins, asdescribed above, while the cartridge supporting portions 40 provided atthe front side corners of the main cartridge body unit 5 are left asplain surfaces and are supported by the height setting pins. Inparticular, in the disc cartridge 1 according to the present invention,the front surface of the main cartridge body unit 5 operating as theinserting end into the recording and/or reproducing apparatus is formedas a continuous arcuate surface having a radius larger than that of thearc of the disc housing section 11 provided on the lower half cartridge4, so that the region surrounded by the front surface section of themain cartridge body unit 5 and the disc housing section 11 can beincreased in area. Thus, the cartridge supporting portions 40 of anincreased area are supported by the height setting pins constituting thepositioning supporting mechanism provided on the recording and/orreproducing apparatus, so that the disc cartridge can be reliablypositioned and supported in a stabilized state by the height settingpins provided within the recording and/or reproducing apparatus.

Meanwhile, the disc cartridge 1 according to the present inventiondelimits a spacing in which to accommodate the shutter members 25, 26 ina section for the disc housing section 11 in which to accommodate theoptical disc 2. For constituting this spacing, the portions of the lowerhalf cartridge 4 and the cover member 38 are reduced in thickness. Onthe other hand, if the delimiting portions of the spacing for theshutter members 25, 26 are thrust and deformed, this spacing is reducedin area so that smooth movement of the shutter members 25, 26 is notguaranteed.

In the disc cartridge 1 of the present invention, there is left in thefront side corners of the main cartridge body unit 5 a large-sizedregion which is not the disc housing section 11 nor a region formovement of the shutter members 25, 26, this region being used as thecartridge supporting portion 40. Therefore, if the shutter members 25,26 are adapted for movement along the bottom of the main cartridge bodyunit 5, and there is provided a spacing in the bottom of the maincartridge body unit 5 for accommodating the shutter members 25, 26, themain cartridge body unit 5 can be supported with correct positioningalong the height in a stabilized state by the height setting pinsprovided in the recording and/or reproducing apparatus, while smoothmovement of the shutter members 25, 26 is assured.

Referring to the drawings, the operation of inserting theabove-described disc cartridge 1 into the recording and/or reproducingapparatus and subsequently ejecting the disc cartridge 1 from therecording and/or reproducing apparatus is explained.

In the non-use state of the disc cartridge 1, that is in the storagestate in which the disc cartridge is not loaded in position in therecording and/or reproducing apparatus, the first shutter member 25 isplaced in a position of closing mainly the recording and/or reproducingopening 15, with the second shutter member 26 being at a position ofclosing mainly the driving opening 16, as shown in FIG. 4. With thepresent disc cartridge 1, since the second shutter member 26 is abuttedagainst the first shutter member 25 inhibited as to the opening/closureoperation by the lock pawl 30 a of the lock member 30 engaging with theshutter retention opening 29, the shutter members 25, 26 cannot be movedunless this locking state is released. In the non-use state, the disccartridge 1 closes the cut-out 3 b formed in the front surface 3 a bythe movement guide portion 25 b of the first shutter member 25, as shownin FIG. 2.

In the loaded state of the disc cartridge 1 in the recording and/orreproducing apparatus, the positioning pins for setting the positions inthe horizontal direction and in the height-wise direction, constitutingthe positioning mechanism provided in the recording and/or reproducingapparatus, are engaged in the engagement holes provided in thepositioning portions 9, while supporting the peripheral portions of thepositioning portions 9. On the other hand, the height setting pinssupport the flat cartridge supporting portions 40, 40 provided on bothcorners on the front surface of the main cartridge body unit 5, so thatthe disc cartridge 1 is loaded with positioning in the horizontaldirection and in the height-wise direction within the recording and/orreproducing apparatus.

When the disc cartridge 1 is inserted into the recording and/orreproducing apparatus, a shutter opening/closure member of the shutteractuating mechanism provided on the recording and/or reproducingapparatus is engaged in the engagement groove 17 for the shutteropening/closing member provided on one side of the main cartridge bodyunit 5, so that the unlock lever 30 b of the lock member 30 protrudedinto the engagement groove 17 for the shutter opening/closing member isthrust in the direction indicated by arrow C1 in FIG. 4. Since the lockmember 30 is rotationally supported by the supporting shaft 21, thedistal end of the lock pawl 30 a is rotated in the direction opposite tothat indicated by arrow D in FIG. 4 when the unlock lever 30 b is thrustin the direction indicated by arrow C1 in FIG. 4, so that the distal endof the lock pawl 30 a is disengaged from the shutter retention opening29. When the distal end of the lock pawl 30 a is disengaged from theshutter retention opening 29, the first shutter member 25 is releasedfrom the state of retention.

When the disc cartridge 1 is inserted further into the recording and/orreproducing apparatus, the shutter opening/closure member is movedfurther in the direction indicated by arrow C1 in FIG. 4 in theengagement groove 17 for the shutter opening/closing member, until theshutter opening/closure member is engaged with the actuating lug 28provided on the actuating portion 25 c of the first shutter member 25.When the actuating lug 28 is engaged in the shutter opening/closuremember, the actuating portion 25 c is pulled into the engagement groove17 for the shutter opening/closing member. If, as shown in FIG. 4, theactuating portion 25 c is pulled into the engagement groove 17 for theshutter opening/closing member, the first shutter member 25 is rotatedto open the recording and/or reproducing opening 15, as shown in FIGS. 6and 8. If, in the disc cartridge 1, the recording and/or reproducingopening 15 is opened, as shown in FIG. 8, the recess 15 d provided inthe movement guide portion 25 b is positioned in the cut-out 3 b intowhich is intruded the recording/reproducing mechanism, such as anoptical pickup, provided on the recording and/or reproducing apparatus,for opening the front surface of the main cartridge body unit 5. Therecording/reproducing mechanism of the recording and/or reproducingapparatus can be approached and intruded into the disc cartridge 1 byopening the cut-out 3 b.

If the first shutter member 25 is rotated in the direction of openingthe recording and/or reproducing opening 15, the second shutter member26 is rotated about the engagement pin 33 as center, in the directionindicated by arrow B1 in FIG. 6, against the bias of the torsion coilspring 34, by the guide protrusion 27 whose position is changed withrotation of the first shutter member 25. When rotated to the positionregulating the rotation of the first shutter member 25, the secondshutter member 26 opens the driving opening 16, as shown in FIGS. 6 and8.

When the disc cartridge 1 is introduced into the inside of the recordingand/or reproducing apparatus until the recording and/or reproducingopening 15 and the driving opening 16 are opened, the disc cartridge 1is positioned and supported by the positioning mechanism, as describedabove, and is loaded on the disc table of the rotational drivingmechanism. If the rotational driving mechanism is run in operation forrotationally driving the optical disc 2 and for driving therecording/reproducing mechanism, such as an optical pickup, informationsignals are recorded on the optical disc, or the information signalsrecorded on the optical disc are reproduced.

If, after end of recording of information signals on the optical disc 2,or end of reproduction of information signals recorded on the opticaldisc, the disc cartridge 1 is to be ejected from the recording and/orreproducing apparatus, an ejection mechanism is actuated for shiftingthe shutter opening/closure member of the shutter actuating mechanism inthe direction indicated by arrow C2 in FIG. 6. This thrusts theactuating lug 28 by the shutter opening/closure member to move theactuating lug 28 in the same direction to rotate the first shuttermember 25 in the direction indicated by arrow A2 in FIG. 6 for closingthe recording/reproducing opening 15. If the first shutter member 25 isrotated in the direction of closing the opening 15, the second shuttermember 26 also is rotated, under the bias of the torsion coil spring 34,in the direction indicated by arrow B2 in FIG. 6, to close the drivingopening 16.

When the first shutter member 25 is restored to the initial positionshown in FIG. 4, the lock pawl 30 a of the lock member 30 is againengaged in the shutter retention opening 29 formed in the actuatingportion 25 c so as to be held in the position of closing the recordingand/or reproducing opening 15 as indicated in FIGS. 2 and 4. If thefirst shutter member 25 is rotated to the position of closing theopening 15, the second shutter member 26 abutted against the firstshutter member 25 also is retained against the bias of the torsion coilspring 34 to close the recording and/or reproducing opening 15 and thedriving opening 16.

Meanwhile, the shutter mechanism 23 provided in the disc cartridge 1according to the present invention is configured for opening/closing therecording and/or reproducing opening 15 and the driving opening 16 bythe first and second shutter members 25, 26. The first and secondshutter members 25, 26 are configured for being overlapped with eachother to preclude a gap otherwise produced in the abutting portion whenthe first and second shutter members 25, 26 have been rotated to theposition of closing the opening 15 and the driving opening 16. In theillustrated embodiment, a step 25 a is provided on one side of the firstshutter member 25, as shown in FIG. 8, so that, when the first andsecond shutter members 25, 26 have been rotated to the position ofclosing the openings 15, 16, the second shutter member 26 is partiallyoverlapped on a step 25 a to close the openings 15, 16 completely, asshown in FIG. 2. Since the openings 15, 16 are closed as the first andsecond shutter members 25, 26 are partially overlapped with each other,it is possible to prevent dust and dirt from entering the inside of themain cartridge body unit 5 via the abutting portions of the first andsecond shutter members 25, 26.

Since the recording and/or reproducing opening 15 and the drivingopening 16 in the present disc cartridge 1 are opened and closed by thefirst and second shutter members 25, 26 which are split and are rotatedalong the bottom side major surface of the main cartridge body unit 5,it is possible to constitute the openings 15, 16 with sizes larger thanthe size of the main cartridge body unit 5. That is, since the recordingand/or reproducing opening 15 and the driving opening 16 can be largerin size than the openings provided on the conventional disc cartridgeopened and closed by a shutter member movable along a lateral side ofthe main cartridge body portion, it is possible to use a recordingmedium of the recording and/or reproducing apparatus having alarge-sized optical pickup device having plural object lenses.

Moreover, since the recording and/or reproducing opening 15 and thedriving opening 16 are provided for extending along the direction ofinsertion of the disc cartridge 1 into the recording and/or reproducingapparatus, the disc cartridge can be easily loaded on the recordingand/or reproducing apparatus in which the rotational driving mechanismand recording and/or reproducing means, such as an optical pickupdevice, are arranged in tandem, for extending along the disc cartridgeinserting direction.

Also, with the disc cartridge 1 of the present invention, the first andsecond shutter members 25, 26 are opened/closed in unison by theactuating portion 25 c being actuated in the direction of being insertedinto and detached from the recording and/or reproducing apparatus. Thus,with the recording and/or reproducing apparatus, it is only sufficientif a bar-shaped pin, for example, is provided in a direction towards theentrance/exit opening, as a shutter opening/closure member adapted foropening the shutter mechanism 23 of the disc cartridge 1, thussimplifying the loading mechanism for the disc cartridge 1.

Since the shutter mechanism 23 in the disc cartridge 1 of the presentinvention is opened or closed by the actuating portion 25 c provided forextending along the lateral side of the main cartridge body unit 5,there is no limitation imposed on the shape of the front side of themain cartridge body unit 5 by the shutter mechanism 23. Although thefront side of the main cartridge body unit 5 is arcuate in the abovedescription, the front side of the main cartridge body unit 5 may beshaped freely insofar as it is not collided against the optical disc 2housed therein.

In the disc cartridge 1 according to the present invention, the shutterportion 25 a, movement guide portion 25 b and the actuating portion 25 cof the first shutter member 25 may be formed as one from the samematerial, or from different materials, and subsequently combinedtogether. That is, the shutter portion 25 a, movement guide portion 25 band the actuating portion 25 c of the first shutter member 25 may beformed of suitable materials depending on the physical properties, suchas resiliency or durability required of these components.

Although the recording and/or reproducing opening 15 and the drivingopening 16 are formed in the lower half cartridge 4, it is also possibleto form similar openings in the upper half cartridge 3 and to providethe upper half cartridge 3 with the shutter mechanism 23.

A modification of the disc cartridge according to the present inventionis now explained.

Referring to FIG. 9, a disc cartridge 50 houses an optical disc 51 forrotation in a main cartridge body unit 54 constituted by an upper halfcartridge 52 and a lower half cartridge 53.

The optical disc 51, housed in the main cartridge body unit 54, has acenter opening 55 and a hub 51 a formed of a magnetic material, such asa metal plate, for closing the center opening 55. The optical disc 51 isset on a disc table of a rotational driving mechanism of the recordingand/or reproducing apparatus and has a hub 51 a attracted by a magnetprovided on the disc table so that the optical disc 51 will be rotatedin unison with the disc table. When the optical disc 55 is loaded on thedisc table, a centering portion provided at the center of the disc tableis engaged with the center opening 55 to achieve centering in which thecenter of rotation of the optical disc 51 is coincident with the centerof rotation of the disc table.

The main cartridge body unit 54, rotationally housing the optical disc51, is combined from an upper half cartridge 52 and a lower halfcartridge 53 abutted and connected to each other. The upper halfcartridge 3 and the lower half cartridge 4 are substantially rectangularin shape and molded from synthetic resin, as shown in FIG. 9.

The upper half cartridge 52, constituting the main cartridge body unit54, has an upstanding peripheral wall 8 constituting a peripheral wallof the main cartridge body unit 54. The upper half cartridge 52 has afront surface 52 a, as an inserting end of the upper half cartridge 52into the recording and/or reproducing apparatus, presents a continuousarcuate surface. The front surface 52 a of the upper half cartridge 52also operates as a front surface of the main cartridge body unit 54. Theopposite lateral surfaces of the main cartridge body unit 54perpendicular to the front surface 52 a of the upper half cartridge 52operating as the inserting end into the recording and/or reproducingapparatus are formed as flat surfaces to permit the inserting end intothe recording and/or reproducing apparatus to be recognized as such. Thedisc cartridge can also be distinguished from the rectangular disccartridge, having flat lateral sides, widely recognized as the disccartridge.

Since only the front surface 52 a of the upper half cartridge 52constituting the front surface of the main cartridge body unit 54 isformed as an arcuate surface, while the lateral surfaces thereofperpendicular to the front surface 52 a are linear flat surfacesparallel to each other, these lateral surfacers act as inserting guidesurfaces at the time of insertion and detachment with respect to therecording and/or reproducing apparatus to realize stable lateralsurfaces of the recording and/or reproducing apparatus.

With the disc cartridge 50, only the front surface 52 a thereofoperating as an inserting end into the recording and/or reproducingapparatus is designed as an arcuate surface, the disc cartridge 50 canbe reduced in plan size as compared to the optical disc 52 housedtherein to permit reduction in size of the recording and/or reproducingapparatus employing the disc cartridge 50.

The corners on the back side opposite to the arcuately-shaped frontsurface 52 a of the upper half cartridge 52 are formed with tubularpositioning portions 57 engaged by positioning pins constitutingpositioning means provided on the recording and/or reproducingapparatus. Each of the positioning portions 57 has its distal end openedand has its proximal end closed by the upper half cartridge 52.

The lower half cartridge 53, abutted against the upper half cartridge 52to constitute the main cartridge body unit 54, is arcuate with a radiussmaller than that of the front surface 53 a of the upper half cartridge52. That is, an arcuate front surface 53 a of the lower half cartridge53 is arcuate with a radius smaller than that of the front surface 52 aof the upper half cartridge 52, as shown in FIG. 9. The portions of thelower half cartridge 53 other than the front surface 53 a are shapedsimilarly to the upper half cartridge 52. That is, the opposite lateralsides perpendicular to the front surface 53 a of the lower halfcartridge 53 is arcuate with a radius smaller than that of the frontsurface 53 a of the lower half cartridge 53, as shown in FIG. 9. Theportions of the lower half cartridge 53 other than the front surface 53a are shaped similarly to the upper half cartridge 52. That is, theopposite lateral sides perpendicular to the front surface 53 a of thelower half cartridge 53 are parallel to each other, with the backsurface opposite to the front surface 53 a being formed as planarsurfaces.

On the inner major surface of the lower half cartridge 53 is formedupright an arcuate housing section forming wall 58 constituting acircular disc housing section 59. This housing section forming wall 58has the same radius of curvature as that of the front surface 53 a. Onthe outer perimeter of the lower half cartridge 53 is formed anupstanding peripheral wall 60 abutted against the upstanding peripheralwall 56 constituting the peripheral wall of the main cartridge body unit54 formed upright on the outer rim of the upper half cartridge 52. Insubstantially triangular regions of the back surface side of the lowerhalf cartridge 53 surrounded by the upstanding peripheral wall 60 andthe housing section forming wall 58, there are formed holes 61 intowhich are fitted the positioning portions 57 provided on the upper halfcartridge 52.

Referring to FIG. 9, the lower half cartridge 53 is formed with arecording and/or reproducing opening 62 and a driving opening 63. Therecording and/or reproducing opening 62 is adapted for exposing aportion of the signal recording region of the optical disc 51 housed inthe disc housing section 59 to outside across the inner and outer rimsof the disc, and for facing recording and/or reproducing means, such asan optical pickup device, while the driving opening 63 is adapted topermit entrance of a turntable of the rotational driving mechanismprovided on the recording and/or reproducing apparatus. In the presentdisc cartridge 50, the recording and/or reproducing opening 62 is formedin continuation with the driving opening 63.

Referring to FIG. 9, the recording and/or reproducing opening 62 isformed substantially as a rectangular opening extending from thevicinity of the mid portion of the disc housing section 59 up to thefront surface 53 a of the lower half cartridge 53. This opening 52,continuing to the driving opening 63, is formed by opening the frontsurface 53 a of the lower half cartridge 53. The driving opening 63 issubstantially circular and is positioned at a Mid portion of the dischousing section 59. On the periphery of the inner rim of the drivingopening 63 is formed a disc supporting portion 63 a supporting the rimof the center opening 55 of the optical disc 51 housed in the dischousing section 59.

In the main cartridge body unit 54, since the front surface 53 a of thelower half cartridge 53 has a curvature larger than the curvature of thefront surface 52 a of the lower half cartridge 52, the corners of thefront surface of the upper half cartridge 52 are protruded from thecorners on the upper half cartridge 52 when the upper and lower halfcartridges 52, 53 are abutted against each other, as shown in FIG. 10.The upstanding peripheral wall 56, formed on the portion of the upperhalf cartridge 52 protruded from the lower half cartridge 53, is formedto a height corresponding to the thickness of the main cartridge bodyunit 54.

In a lateral surface perpendicular to the front surface of the maincartridge body unit 54 is formed an engagement groove 64 for a shutteropening/closing member. When the upper and lower half cartridges 52, 53are abutted against each other, the engagement groove 64 for a shutteropening/closing member is abutted against a groove 64 a formed in theupstanding peripheral wall 56 of the upper half cartridge 52 and againsta recess 64 b formed in the upstanding peripheral wall 60 on the lowerhalf cartridge 53. When the disc cartridge 50 is inserted into therecording and/or reproducing apparatus, a shutter opening/closing memberconstituting the shutter opening/closing mechanism provided on therecording and/or reproducing apparatus is engaged in the engagementgroove 64 for a shutter opening/closing member for movement therein. Theengagement groove 64 for a shutter opening/closing member is formed witha through-hole 65 into which is protruded part of a lock member 77 aslater explained.

The front surface 52 a of the upper half cartridge 52 constituting themain cartridge body unit 54 is formed with an inner wall 66 having thesame curvature as that of the front surface 53 a of the lower halfcartridge 53. When the upper and lower half cartridges 52, 53 areabutted against each other, as shown in FIGS. 10 and 11, the inner wallsection 66 is abutted against the inner surface of the lower halfcartridge 53 along the outer periphery of the arcuate housing sectionforming wall 58 provided on the lower half cartridge 53. In the innerwall section 66 of the upper half cartridge 52 and in housing sectionforming wall 58 of the lower half cartridge 53 is formed a shutter guidegroove 67 for guiding the opening/closure movement of a first shuttermember 71 of the shutter mechanism 69, as shown in FIGS. 10 and 11.

At both corners towards the front surface of the main cartridge bodyunit 54 are formed a pair of substantially triangular regions surroundedby the upstanding peripheral wall 56 and the inner wall section 66 ofthe upper half cartridge 52, as shown in FIG. 10. In a region of themain cartridge body unit 54 provided with the engagement groove 64 for ashutter opening/closing member provided in the main cartridge body unit54, there is protruded a supporting shaft 68 for rotationally supportingthe lock member 77, as shown in FIG. 10.

In the bottom surface of the lower half cartridge 53 constituting themain cartridge body unit 54, there is provided a recessed shuttermounting portion 70 in which to mount the shutter mechanism 69 adaptedfor opening/closing the recording and/or reproducing opening 62 and thedriving opening 63. The shutter mounting portion 70 is formed over anextent through which is slid the shutter mechanism 69 foropening/closing the recording and/or reproducing opening 62 and thedriving opening 63.

The shutter mechanism 69 arranged on the shutter mounting portion 70 ismade up of a first shutter member 71 for opening/closing the recordingand/or reproducing opening 62 and a second shutter member 72 foropening/closing the driving opening 63. The first shutter member 71 andthe second shutter member 72 are arranged with an overlap at the endsoperating as the center of rotation, with other portions of the firstand second shutter members 71, 72 being arranged on the co-planar planein the shutter mounting portion 70.

The first shutter member 71 is formed of synthetic resin or metal and ismade up of a shutter portion 71 a, formed as a flat plate, a movementguide portion 71 b formed upright on a side of the shutter portion 71 a,and an actuating portion 71 c protruded from one end of the movementguide portion 71 b, as shown in FIG. 9. The first shutter member 71 ismounted on the main cartridge body unit 54, with the shutter portionshutter portion 71 a being positioned in the shutter mounting portion 70formed in the lower half cartridge 53 and with the movement guideportion 71 b and the actuating portion 71 c being positioned in theshutter guide groove 67. The shutter portion shutter portion 71 a isformed as substantially trapezoidal shape of a size sufficient to closethe recording and/or reproducing opening 62, and carries on its lateralside an arcuate portion of the same curvature as that of the frontsurface 53 a of the lower half cartridge 53. This shutter portionshutter portion 71 a is rotated in the direction indicated by arrowsEngagement groove 17 for a shutter opening/closing member and E2 in FIG.10 with the center of the disc housing section 59 as virtual center, foropening/closing the recording and/or reproducing opening 62. The shutterportion 71 a is abutted against the second shutter member 72 along thearcuate-shaped lateral surface.

The movement guide portion 71 b is formed subsequently upright withrespect to the shutter portion shutter portion 71 a for extending alongan arcuate portion formed on one side of the shutter portion shutterportion 71 a. This movement guide portion 71 b is formed in an arcuateshape of the same radius of curvature as that of the shutter guidegroove 67 and is arranged for movement therein in the directionindicated by arrows Engagement groove 17 for a shutter opening/closingmember and E2 in FIG. 10. The movement guide portion 71 b is of a lengthlonger than the arcuate portion of the shutter portion shutter portion71 a to reach the vicinity of an end of a shutter guide groove 67 tocontrol the movement of the first shutter member 71 so that the latterwill not be moved in excess of a pre-set distance in the directionindicated by arrow E2 in FIG. 10. The movement guide portion 71 b isprovided with a recess 71 d into which is intruded therecording/reproducing mechanism, such as an optical pickup, when theshutter mechanism 69 is opened.

In the closure position of the shutter mechanism 69, the movement guideportion 71 b closes the cut-out 3 b formed in the front side of the maincartridge body unit 54. When the shutter mechanism 69 is opened, therecess 71 d is moved to the cut-out 3 b to create an opening in thefront side which will permit the optical disc 51 to be exposed tooutside. By providing the recess 71 d in the disc cartridge 50, therecording/reproducing mechanism provided on the recording and/orreproducing apparatus can be moved towards the optical disc 51. Byreducing the distance between the optical disc 51 and therecording/reproducing mechanism in this manner, it is possible to reducethe thickness of the recording and/or reproducing apparatus.

The actuating portion 71 c provided on the first shutter member 71 isformed as an elastic or resilient member, and is of a thickness thinnerthan the movement guide portion 71 b. Similarly to the movement guideportion 71 b, the actuating portion 71 c is arranged within the shutterguide groove 67, with the distal end of the movement guide portionprotruding into the engagement groove 64 for a shutter opening/closingmember, as shown in FIG. 10. At the distal end of the actuating portion71 c, exposed to the engagement groove 64 for a shutter opening/closingmember, there is formed an actuating lug 75. The actuating portion 71 cis pulled into the inside of the engagement groove 64 for a shutteropening/closing member, by the actuating lug 75 engaging with shutteropening/closure member of the shutter actuating mechanism provided onthe recording and/or reproducing apparatus so as to be thrust by theshutter opening/closure member in the direction indicated by arrow G1 inFIG. 10, with the actuating lug 75 being then moved within theengagement groove 64 for a shutter opening/closing member. Partway inthe actuating portion 71 c is bored a shutter retention opening 76. Thisshutter retention opening 76 is engaged by a lock pawl 77 a of the lockmember 77 which is arranged in a substantially triangular recessprovided in a region between the upstanding peripheral wall 56 and theinner wall section 66 of the upper half cartridge 52 and which isrotationally supported by a supporting shaft 68. The opening/closuremovement of the first shutter member 71 is controlled by the lock pawl77 a of the lock member 77 engaging in the shutter retention opening 76of the actuating portion 71 c.

The lock member 77 includes a lock pawl 77 a, an unlock lever 77 b,partially protruded from a through-hole 65 formed in the engagementgroove 64 for the shutter opening/closing member, and an elastic member77 c, such as a spring plate, which biases the lock member 77 in thedirection indicated by arrow H in FIG. 10, that is in a direction ofengaging the distal end of the lock pawl 77 a in the shutter retentionopening 76.

The second shutter member 72 is formed of, for example, synthetic resinor metallic material, and is of a width sufficient to close the drivingopening 63. The second shutter member 72 includes two pins 78 on itsmajor surface that are fitted into an operating guide groove 80 forguiding the trajectory of the opening/closure movement to control thetrajectory of the shutter opening/closure operation.

The shutter mechanism 69 is configured so that the first shutter member71 and the second shutter member 72 are fitted in an elongated openingfor rotation 74 provided in the second shutter member 72 so that theoperation of one of the shutter members occurring in association withthat of the other member for opening or closing the openings. Also, inthe shutter mechanism 69, the portion of the second shutter member 72formed with an opening for rotation 76 is stepped so that the thus, withthe shutter mechanism 69, the stepped portion of the second shuttermember 72 is placed within a sliding portion 79 in which the shuttermounting portion 70 is arranged as a recess.

When the upper half cartridge 52 and the lower half cartridge 53 areabutted against and bonded to each other by thermal fusion or with anadhesive to form the main cartridge body unit 54, and the shuttermechanism 69 is arranged on the shutter mounting portion 70 provided onthe main cartridge body unit 54, there is mounted a cover member 81 onthe bottom side of the main cartridge body unit 54, that is on the sideof the lower half cartridge 53 carrying the shutter mounting portion 70.The portion of the cover member 81 in register with the recording and/orreproducing opening 62 and the driving opening 63 is cut out, whilethere is formed a cut-out 81 a at a position in register with thepositioning portion 57 provided on the upper half cartridge 52 forexposing the opening end of the positioning portion 57 to outside. Thecover member 81 holds the shutter mechanism 69 arranged on the shuttermounting portion 70 to prevent the intrusion of dust and dirt into theinside of the main cartridge body unit 54. The cover member 81 issecured, such as with an adhesive, to the main cartridge body unit 54.The disc cartridge 50 is formed in the lower half cartridge 53 with therecording and/or reproducing opening 62 and the driving opening 63, asfirst openings, and with a cut-out in the cover member 81, as a secondopening, to provide the openings operative to expose the center opening55 of the recording region of the optical disc 51 to outside.

Meanwhile, since the shutter member provided on the routine disccartridge is mounted exteriorly of the main cartridge body unit, and ismoved along the outer surface of the main cartridge body unit, the dustand dirt affixed to the outer surface of the main cartridge body unit isaffixed to the back side of the shutter member at the time of theshutter member to descend into the inside of the disc housing section.

In the disc cartridge 1 of the present invention, the first shuttermember 71 and the second shutter member 72 are provided in the housingspace defined between the inner wall constituted by the outer surface ofthe lower half cartridge 53 of the main cartridge body unit 54 and thecover member 81 arranged in an overlapping relation on the inner wall toconstitute the outer wall, so that there is no risk that the dust anddirt affixed to the outer side of the main cartridge body unit 5 beintruded into the inside of the cartridge housing section 59. That is,the first and second shutter members 71, 72 are not moved along theouter sides of the main cartridge body unit 54 where dust and dirt areliable to be deposited, but are moved within the inside of the maincartridge body unit 54, so that dust anddirt affixed to the outersurface of the main cartridge body unit 54 are positively prevented fromentering the inside of the cartridge housing section 59 to assurereliable protection of the optical disc 51 housed in the main cartridgebody unit 54.

In the disc cartridge 50 of the present invention, a cartridgesupporting portion 82 supported by a positioning pin constituting apositioning mechanism provided on the recording and/or reproducingapparatus for setting the position along the height and in thehorizontal direction and by a height setting pin setting the position inthe height-wise direction is provided at each of four corners of themain cartridge body unit 54 outwardly of the shutter mounting portion70, that is outside the range of movement of the shutter mechanism 69,as shown in FIG. 13. The cartridge supporting portions 82, provided onthe back side corners of the main cartridge body unit 54, are providedwith positioning portions 57 engaged by the positioning pins, while thecartridge supporting portions 82 provided at the front side corners ofthe main cartridge body unit 54 are left as plain surfaces and aresupported by the height setting pins. In particular, in the disccartridge 50 according to the present invention, the front surface ofthe main cartridge body unit 54 operating as the inserting end into therecording and/or reproducing apparatus is formed as a continuous arcuatesurface having a radius larger than the arc of the arc of the dischousing section 59 provided on the lower half cartridge 4, so that theregion surrounded by the front surface section of the main cartridgebody unit 54 and the disc housing section 59 can be increased in area.Thus, the cartridge supporting portions 82 of an increased area aresupported by the height setting pins constituting the positioningsupporting mechanism provided on the recording and/or reproducingapparatus, so that the disc cartridge can be reliably positioned andsupported in a stabilized state by the height setting pins providedwithin the recording and/or reproducing apparatus.

In the disc cartridge 50 of the present invention, there is left in thefront side corners of the main cartridge body unit 54 a large-sizedregion which is not the disc housing section 59 nor a region formovement of the shutter members 71, 72, this region being used as thecartridge supporting portion 82. Therefore, if the shutter members 71,72 are adapted for movement along the bottom of the main cartridge bodyunit 54, and there is provided a spacing in the bottom of the maincartridge body unit 54 for accommodating the shutter members 71, 72, themain cartridge body unit 54 can be supported with correct positioningalong the height in a stabilized state by the height setting pinsprovided in the recording and/or reproducing apparatus while smoothmovement of the shutter members 71, 72 is assured.

Referring to the drawings, the operation of inserting theabove-described disc cartridge 50 into the recording and/or reproducingapparatus and subsequently ejecting the disc cartridge 50 from therecording and/or reproducing apparatus is explained.

In the non-use state of the disc cartridge 50, that is in the storagestate in which the disc cartridge is not loaded in position in therecording and/or reproducing apparatus, the first shutter member 71 isplaced in a position of closing mainly the recording and/or reproducingopening 62, with the second shutter member 72 being at a position ofclosing mainly the driving opening 63, as shown in FIG. 10. With thepresent disc cartridge 50, since the second shutter member 72 is abuttedagainst the first shutter members 71, inhibited from the opening/closuremovement by the lock pawl 77 a of the lock member 77 engaging with theshutter retention opening 76, the first and second shutter members 71,72 are inhibited from movement unless this locked state is released.

When the disc cartridge 50 is loaded on the recording and/or reproducingapparatus, the positioning pins for setting the loading position in thehorizontal direction and in the height-wise direction, constituting apositioning mechanism arranged in the recording and/or reproducingapparatus, are engaged in the engagement openings provided in thepositioning portion 57, while supporting the peripheral portion of thepositioning portion 57. In addition, the height setting pins support theflat cartridge supporting portions 82, 82 provided at both corners onthe front side of the main cartridge body unit 54, whereby the disccartridge 50 is loaded in position in the horizontal direction and inthe height-wise direction in the recording and/or reproducing apparatus.

In the non-use state of the disc cartridge 50, that is in the storagestate in which the disc cartridge is not loaded in position in therecording and/or reproducing apparatus, the first shutter member 71 isplaced in a position of closing mainly the recording and/or reproducingopening 62, with the second shutter member 72 being at a position ofclosing mainly the driving opening 63, as shown in FIG. 1. With thepresent disc cartridge 50, the first and second shutter members 71, 72are inhibited from movement unless a locked state is released. It isnoted that the lock pawl 77 a of the lock member 77 is engaged with theshutter retention opening 76 to inhibit the first shutter member 71 fromperforming an opening/closure movement.

When the disc cartridge 50 is inserted into the recording and/orreproducing apparatus, the positioning pins for setting the loadingposition in the horizontal direction and in the height-wise direction,constituting a positioning mechanism arranged in the recording and/orreproducing apparatus, are engaged in the engagement opening provided inthe positioning portion 57, while supporting the peripheral portion ofthe positioning portion 57. In addition, the height setting pins supportthe flat cartridge supporting portions 82, 82 provided at both cornerson the front side of the main cartridge body unit 54, whereby the disccartridge 50 is loaded in position in the horizontal direction and inthe height-wise direction in the recording and/or reproducing apparatus.

The shutter opening/closure member of the shutter actuating mechanismprovided on the recording and/or reproducing apparatus is engaged in theengagement groove 64 for a shutter opening/closing member provided onone side of the main cartridge body unit 54, so that the unlock lever 77b of the lock member 77 protruded into the engagement groove 64 for ashutter opening/closing member is thrust in the direction indicated byarrow G1 in FIG. 10. Since the lock member 77 is rotationally supportedby the supporting shaft 68, the distal end of the lock pawl 77 a isrotated in the direction opposite to that indicated by arrow H in FIG.7, when the unlock lever 77 b is thrust in the direction indicated byarrow G1 in FIG. 10, so that the distal end of the lock pawl 77 a isdisengaged from the shutter retention opening 76. When the distal end ofthe lock pawl 30 a is disengaged from the shutter retention opening 76,the first shutter member 71 is released from the state of retention.

When the disc cartridge 50 is inserted further into the recording and/orreproducing apparatus, the shutter opening/closure member is movedfurther in the direction indicated by arrow G1 in FIG. 10 in theengagement groove 64 for the shutter opening/closing member, until theshutter opening/closure member is engaged with the actuating lug 75provided on the actuating portion 71 c of the first shutter member 71protruded into the engagement groove 64 for a shutter opening/closingmember. When the actuating lug 75 is engaged in the shutteropening/closure member, the actuating portion 71 c is pulled into theengagement groove 64 for the shutter opening/closing member. If, asshown in FIG. 12, the actuating portion 71 c is pulled into theengagement groove 64 for a shutter opening/closing member, the shuttermember shutter portion shutter portion 71 a and the movement guideportion 71 b are rotated to open the recording and/or reproducingopening 62, as shown in FIG. 12.

In the disc cartridge 50, the first shutter member 71 and the secondshutter member 72 are rotated in the direction indicated by arrow F1 inFIG. 7, in association with the movement of the supporting shaft forrotation 73 fitted in the elongated opening for rotation 74 to open thedriving opening 63.

If the disc cartridge 50 is inserted into the inside of the recordingand/or reproducing apparatus up to a position of opening the recordingand/or reproducing opening 62 and the driving opening 63, the disccartridge 50 is loaded on the cartridge loading section within therecording and/or reproducing apparatus, as it is positioned andsupported by the positioning mechanism, until the disc cartridge isloaded on the disc table of the rotational driving mechanism. Therotating driving mechanism then is driven for rotationally driving theoptical disc 51, while the recording/reproducing mechanism, such as anoptical pickup, is driven for recording information signals on theoptical disc 51 or reproducing the information signals recorded on theoptical disc 51.

If after the recording of the information signals on the optical disc51, or after the end of reproduction of the information signals recordedon the optical disc 51, the disc cartridge 50 is to be ejected from therecording and/or reproducing apparatus, an ejection mechanism isactuated to cause movement of the shutter opening/closure member of theshutter actuating mechanism in the direction indicated by arrow G2 inFIG. 12. This causes the actuating lug 75 to be thrust by the shutteropening/closure member and moved in the same direction to cause rotationof the first shutter member 71 in the direction indicated by arrow E2 inFIG. 12 to close the opening 62. If the first shutter member 71 isrotated in the direction of closing the first shutter member 62, thesecond shutter member 72 also is pulled by the supporting shaft 73fitted in the elongated opening for rotation 74 so as to be rotated inassociation with the operation of the supporting shaft 73 in thedirection indicated by arrow F2 in FIG. 12 to close the driving opening63.

When the first shutter member 71 is returned to the initial positionshown in FIG. 10, the lock pawl 77 a of the lock member 77 is againengaged in the shutter retention opening 76 formed in the actuatingportion 71 c so that the first shutter member 71 is held in the positionof FIG. 10 to close the recording and/or reproducing opening 62. Whenthe first shutter member 71 has been rotated to the position of closingthe opening 62, the second shutter member 72, rotated in unison with thefirst shutter member 71, is also held in the position of closing thedriving opening 63 to close both the recording and/or reproducing 62 andthe driving opening 63.

1. A disc cartridge for housing a disc-shaped recording medium adaptedfor recording and/or reproducing information signals thereon when loadedin a recording and/or reproducing apparatus, comprising: a disc-shapedrecording medium; a main cartridge body unit including a circular mediumhousing section for rotationally accommodating the disc-shaped recordingmedium and having an opening including a recording and/or reproducingopening portion for exposing at least a portion of the disc-shapedrecording medium and a driving opening portion for allowing intrusion ofrotation driving means for rotationally driving said disc-shapedrecording medium, said recording and/or reproducing opening portionbeing formed continuous with said driving opening portion; and a shuttermechanism including a first shutter member for opening/closing a firstopening portion formed at an inserting side of said opening which isfirstly inserted into the recording and/or reproducing apparatus, and asecond shutter member for opening/closing a second opening portionformed at a side opposite to the inserting side, said second shuttermember primarily opening/closing said driving opening portion, whereinsaid first and second shutter members are substantially coplanar.
 2. Thedisc cartridge according to claim 1 wherein said first and secondshutter members are mounted in a co-planar relationship and rotate alonga major surface of said main cartridge body unit so as to open/closesaid opening.
 3. The disc cartridge according to claim 1 wherein saidmain cartridge body unit has a pair of front side corners and a pair ofback side corners; said disc cartridge further comprising: a cartridgesupporting portion provided at each of said front side corners and saidback side corners outside a shutter region of the main cartridge bodyunit, said cartridge supporting portions provided at said pair of backside corners including positioning portions which are adapted to beengaged by positioning pins of positioning means of the recording and/orreproducing apparatus, and said cartridge supporting portions providedat said pair of front side corners are plane surfaces adapted to besupported by height setting pins of said positioning means of therecording and/or reproducing apparatus so as to stably load the disccartridge in the recording and/or reproducing apparatus.